Re: IR35, is currently costing the taxpayer around £440m a year
But if HMRC really have ignored how the contract "actually works", you'll be able to convince a judge and he'll chuck it out.
Yep. I have seen several reports which say that HMRC lose the vast majority of IR35 cases which go to tribunal. This is why they are trying to change the rules, to force (unnecessary) tax and NI to be taken at source, and force PSC consultants to take them to tribunal to get it back. They think (hope) that most won't bother.
That said, if I was consulting for the public sector, I would be upping my rates in April to cover any extra tax which will be imposed, as well as considering a move to the private sector. It's ridiculous to think that agencies or government departments will be willing to take the risk under these rules: Most will just blindly force consultants to work on payroll, obviously without giving them any of the rights of an employee.